Comparison of attenuation characteristics of the acoustic reflex and the V-51R earplug.

COMPARISON OF ATTENUATION CHARACTERISTICS OF THE ACOUSTIC REFLEX AND THE V-5IR EARPLUG OBJECT To compare the attenuation characteristics of the acoustic reflex and the V-5IR earplug, RESULTS Pre-and post-exposure thresholds were obtained for 13 subjects exposed under two conditions to 100 rounds of machine gun fire (fired one round at a time). In condition I the acoustic reflex (AR) was activated to protect the listener and in condition II protection was afforded by the V-51R earplug. Results show protection by the AR superior to that of the V-5iR up to 1000 cps, markedly inferior at and above 2000 cps. RECOMMENDATIONS It is recommended that: 1. The AR be utilized as an ear protective mechanism where low frequency noise of an impulse type predominates. 2. Further research should be done to study possible extensions of the usefulness of the AR as a protective mechanism. Specifically, steps should be taken to develop and test an AR ear protective device. Crew members in armored vehicles undergo considerable exposure to firing during training. Organic to armored vehicles is a radio intercom system. Suitability of this system as part of an AR protective device should be investigated